Methods and apparatus for self optimization and/or improvement of a cloud-based wireless network

ABSTRACT

In some embodiments, an apparatus includes a monitor module configured to monitor a set of performance indicators associated with a first network topology of a wireless network provider system. In the first network topology, a set of virtual baseband units services a set of remote radio heads. The apparatus includes a detector module configured to detect an operational condition of the wireless network provider system based on at least one value associated with the set of performance indicators at a first time. The apparatus further includes an optimization module configured to define, based on the operational condition, a second network topology for the set of virtual baseband units. The optimization module is further configured to send a signal to a virtual baseband unit pool manager to configure the wireless network provider system in the second network topology at a second time after the first time.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 62/057,814 (Attorney Docket No. REVB-019/00US 315256-2054),filed on Sep. 30, 2014, and entitled “Methods and Apparatus for SelfOptimization and/or Improvement of a Cloud-Based Wireless Network,” thecontents of which are incorporated herein by reference in its entirety.

BACKGROUND

Some embodiments described herein relate generally to systemoptimization mechanisms for wireless networks, and, in particular, tomethods and apparatus for dynamic virtualization and optimization in acloud-based wireless network.

With the number of mobile users rapidly rising, a growing demand existsfor mobile broadband while reducing operational expenses for operatorsof wireless networks. Some known wireless networks implement a networkoptimization process to find improved configurations and improve theperformance for the wireless networks. Such known wireless networkstypically rely on a static relationship between remote radio heads(“RRHs”) and baseband units (“BBUs”). Such static optimization processestypically fail to use and position system resources most efficiently andintelligently to obtain optimal coverage and capacity without qualitydegradation.

Accordingly, a need exists for methods and apparatus for implementing acloud-based system that can dynamically change the configuration andtopology to improve the wireless network through control of the BBUs.

SUMMARY

In some embodiments, an apparatus includes a monitor module implementedin at least one of a memory or a processing device of a wireless networkprovider system. The monitor module is configured to monitor a set ofperformance indicators associated with a first network topology. In thefirst network topology, a set of virtual baseband units services a setof remote radio heads of the wireless network provider system. Theapparatus includes a detector module operatively coupled to the monitormodule. The detector module is configured to detect an operationalcondition of the wireless network provider system based on at least onevalue associated with the set of performance indicators at a first time.The apparatus further includes an optimization module operativelycoupled to the detector module. The optimization module is configured todefine, based on the operational condition, a second network topologyfor the set of virtual baseband units. The optimization module isfurther configured to send a signal to a virtual baseband unit poolmanager to configure the wireless network provider system in the secondnetwork topology at a second time after the first time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B are schematic diagrams that illustrate a wireless networkprovider system configured to improve or maximize the overall networkperformance for a wireless network, according to an embodiment.

FIG. 2 is a system block diagram of a cloud network optimization module,according to an embodiment.

FIGS. 3A-3B are block diagrams that illustrate two front haul deploymentoptions, according to an embodiment.

FIG. 4 is a schematic diagram that illustrates a cloud-based wirelessnetwork, according to an embodiment.

FIG. 5 is a flow chart illustrating an optimization method, according toan embodiment.

DETAILED DESCRIPTION

In some embodiments, an apparatus includes a monitor module implementedin at least one of a memory or a processing device of a wireless networkprovider system. The monitor module is configured to monitor a set ofperformance indicators associated with a first network topology. In thefirst network topology, a set of virtual baseband units services a setof remote radio heads of the wireless network provider system. Theapparatus includes a detector module operatively coupled to the monitormodule. The detector module is configured to detect an operationalcondition of the wireless network provider system based on at least onevalue associated with the set of performance indicators at a first time.The apparatus further includes an optimization module operativelycoupled to the detector module. The optimization module is configured todefine, based on the operational condition, a second network topologyfor the set of virtual baseband units. The optimization module isfurther configured to send a signal to a virtual baseband unit poolmanager to configure the wireless network provider system in the secondnetwork topology at a second time after the first time.

In some embodiments, an apparatus includes a memory and a hardwareprocessor operatively coupled to the memory and configured to implementa monitor module, a detector module and an optimization module. Themonitor module is configured to monitor a set of performance indicatorsassociated with a wireless network provider system. The wireless networkprovider system includes a first set of virtual baseband units servicingat a first time a set of remote radio heads to define a first networktopology. The detector module is configured to define an operationcondition of the wireless network provider system, at the first time,when at least one value associated with the set of performanceindicators fails to meet a performance criterion. The optimizationmodule is configured to send a signal to a virtual baseband unit poolmanager, at a second time after the first time, such that the virtualbaseband unit pool manager causes a second set of virtual baseband unitsto service the set of remote radio heads after the second time to definea second network topology different from the first network topology.

In some embodiments, a method includes monitoring a set of performanceindicators associated with a first network topology and/or configurationof a wireless network provider system. The first network topology and/orconfiguration includes a first set of virtual baseband units servicing afirst set of remote radio heads of the wireless network provider system.The method further includes defining, at a first time and based on atleast one value associated with the set of performance indicators, asecond network topology and/or configuration of the wireless networkprovider system. The second network topology and/or configurationincludes a second set of virtual baseband units servicing a second setof remote radio heads of the wireless network provider system. Themethod further includes sending a signal to a virtual baseband unit poolmanager to transition the wireless network provider system from thefirst network topology and/or configuration to the second networktopology and/or configuration at a second time after the first time.

As used herein, a module can be, for example, any assembly and/or set ofoperatively-coupled electrical components, and can include, for example,a memory, a processor, electrical traces, optical connectors, software(executing in hardware) and/or the like.

As used herein, the singular forms “a,” “an” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, the term “a cloud network optimization module” is intended tomean a single physical device or a combination of physical devices.

FIGS. 1A-1B are schematic diagrams that illustrate a wireless networkprovider system 100 configured to improve or maximize the overallnetwork performance of a wireless network 102, according to anembodiment. The wireless network 102 can be any network that enableswireless communication devices (e.g., cellular phones, Wi-Fi enabledlaptops, Bluetooth devices, mobile devices) to communicate with eachother. In some embodiments, the wireless network 102 can be implementedand administered using a wireless transmission system such as radiofrequency (RF) waves. For example, the wireless network 102 can be acellular network that enables cellular phones to communicate with eachother. For another example, the wireless network 102 can be a Wi-Finetwork that enables Wi-Fi enabled laptops to be operatively connected.In some embodiments, the wireless network 102 can be at least a portionof, for example, a wireless local area network (WLAN), a wireless meshnetwork, a wireless metropolitan area network (MAN), a wireless widearea network (WAN), a mobile device network (e.g., a global system formobile communications (GSM) network, a personal communications service(PCS) network), a radio access network (RAN), a long term evolution(LTE) network, a Universal Mobile Telecommunications System (UMTS)network and/or the like. In some embodiments, the wireless network 102can include the connections between multiple base stations (i.e., thebackhaul).

As shown in FIG. 1A, the wireless network provider system 100 includes acloud network optimization module 101, a baseband unit (“BBU”) poolserver 105, a set of virtual BBUs (e.g., virtual BBUs 111, 112, and 113)situated within a virtual BBU hosting device 110, and a set of remoteradio heads (“RRHs”) (e.g., RRHs 151, 152, 153, 154, and 155) connectedto an array of antennas 160 to transmit and receive signals with thewireless network 102. Similarly stated, the antennas 160 can provide thesignals and/or connectivity to define at least a portion of the wirelessnetwork 102. As discussed in detail herein, the topology and/or theconfiguration of the wireless network provider system 100 can be changedand/or reconfigured to optimize and/or improve the performance of thewireless network 102 based on performance indicators associated with thewireless network provider system 100 and/or the wireless network 102.The various components within the wireless network provider system 100can be connected with each other via a wired connection (e.g., fiberoptic, Ethernet, etc.) and/or a wireless connection. The cloud networkoptimization module 101 and/or the BBU pool server 105 can be connected,wired or wirelessly, to a core or public network 103 (e.g., a local areanetwork (LAN)).

The RRHs (e.g., RRHs 151, 152, 153, 154, and 155) include digital-analogconverters and can process signals as specified by, for example, openbase station architecture initiative (“OBSAI”), Common Protocol RadioInterface (“CPRI”), or other propriety digital interfaces. The RRHs canconvert the signals to be transmitted by the set of antennas 160 fromone range of frequencies to another range of frequencies (e.g., frombaseband to radio frequency). For the signals to be received from theset of antennas 160 at the RRHs, the RRHs are also configured to convertthe signals from one range of frequencies to another range offrequencies (e.g., from radio frequency to baseband). In some instances,the RRHs are configured to place and/or modulate signals to be sent bythe antennas 160 onto a carrier frequency. Similarly, in some instances,the RRHs are configured to remove and/or demodulate signals receivedfrom the antennas 160 at the RRHs from a carrier frequency.

The virtual BBUs (e.g., 111, 112, and 113) can be virtual machinesconfigured to implement base station functionalities. In someembodiments, the virtual BBUs are executed and/or instantiated by aprocessor situated in the BBU pool server 105. In some embodiments, thevirtual BBUs are instantiated by a processor situated in a virtual BBUhosting device 110 separate from the BBU pool server 105. Each virtualBBU can be configured to send control signals (or instructions) to oneor many RRHs, and process data received from one or many RRHs. In someembodiments, the virtual BBUs can be instantiated and/or executed by asingle processor at a central location. In other embodiments, the BBUscan be distributed across multiple processors and/or locations. In someembodiments, for example, the virtual BBUs 111-113 can be instantiatedand/or executed across multiple servers within a data center. Thisallows physical servers to be turned off (thus reducing power) when theadditional processing power is not being used by the demands of thewireless network 102.

The BBU pool server 105 is a compute device that can instantiate,terminate and/or reconfigure or reassign the virtual BBUs (e.g., 111,112, and 113). For example, the BBU pool server 105 can have a memory(not shown) and a processor (not shown) configured to execute codestored in the memory to instantiate, terminate and/or reconfigure orreassign the virtual BBUs. The BBU pool server 105 can executeinstructions received from the cloud network optimization module 101 toinstantiate and terminate the virtual BBUs. Moreover, the BBU poolserver 105 can execute instructions received from the cloud networkoptimization module 101 to reconfigure, reassign, and/or rebalance therelationships between the virtual BBUs 111, 112, 113 and the RRHs151-155, as described in further detail herein. Accordingly, based oninstructions received from the cloud network optimization module 101,the BBU pool server 105 can modify a network topology of the virtualBBUs. The BBU pool server 105 is also referred to herein as a virtualbaseband unit pool manager.

The cloud network optimization module 101 can be any compute device orsoftware module configured to optimize or improve the performance of thewireless network 102 by instantiating new virtual BBUs, terminatingexisting virtual BBUs, establishing and/or adjusting the mapping of thevirtual BBUs and the RRHs between one-to-one (e.g., one RRH is assignedto one virtual BBU) and/or one-to-many (e.g., more than one RRHs areassigned to one virtual BBU). In some embodiments, the cloud networkoptimization module 101 can be, for example, a computer device, a serverdevice, an application server, a mobile device, a workstation, and/orthe like. The cloud network optimization module 101 can be, for example,hardware and/or software executing in hardware. For example, the cloudnetwork optimization module 101 can be software executing on the BBUpool server 105. The cloud network optimization module 101 can beoperatively coupled (e.g., directly or indirectly) to the devices withinthe wireless network 102. The cloud network optimization module 101 canbe, for example, operatively coupled to the BBU Pool Server 105 via oneor multiple intermediate modules and/or devices such as, for example, acontroller device, a network, and/or the like (not shown in FIG. 1A).The cloud network optimization module 101 can be, for example, coupledto devices of the wireless network provider system 100 via any suitableconnecting mechanism such as, for example, optical connections (e.g.,optical cables and optical connectors), electrical connections (e.g.,electrical cables and electrical connectors), wireless connections(e.g., wireless transceivers and antennas), and/or the like. While shownin FIG. 1A as a single device, in some arrangements the functionality ofthe cloud network optimization module 101 can be distributed to multipledevices across the wireless network provider system 100.

The cloud network optimization module 101 can be configured to execute avirtualization and optimization processes or methods to reconfigure thetopology of the wireless network provider system 100 to optimize orimprove the performance of the wireless network 102. Such avirtualization and optimization process or method can be executed toimprove the performance of the wireless network 102 from, for example, asuboptimal performance. Additionally, the virtualization andoptimization process can be used to ensure that the available processingcapabilities of the virtual BBUs 111-113 are being effectively used andnot wasted. Specifically, the cloud network optimization module 101 canbe configured to monitor the wireless network 102 and collect or receivepower indications, link connection information, throughput indication,configuration parameters and/or Key Performance Indicators (KPIs) fromthe wireless network 102. Based on the collected or received data, thecloud network optimization module 101 can be configured to detect poornetwork performance in the coverage areas of some RRHs in the wirelessnetwork provider system 100. Moreover, the cloud network optimizationmodule 101 can receive indications of a load on and/or a currentavailable processing power at each virtual BBU 111-113. The cloudnetwork optimization module 101 can then be configured to determine howto establish or adjust the mapping of the virtual BBUs and the RRHs.Based on the optimization decisions, the cloud network optimizationmodule 101 can then be configured to send and/or execute instructions toinstantiate new virtual BBU, terminate existing virtual BBU, establishand/or adjust the mapping of the virtual BBUs and the RRHs betweenone-to-one (e.g., one RRH is assigned to one virtual BBU) and/orone-to-many (e.g., more than one RRHs are assigned to one virtual BBU).The configuration modifications can then be applied at the correspondingdevices.

The cloud network optimization module 101 can define a static or adynamic relationship between the virtual BBUs 111-113, and the RRHs151-155 in substantially real-time. In other instances, virtual BBUs111-113 can be defined and statically associated with RRHs 151-155. Insome instances, as the wireless network traffic load and/or distributionchanges, the cloud network optimization module 101 can, dynamically andin real-time in response to the changes of the wireless network trafficload and/or distribution, and reconfigure the topology of the wirelessnetwork provider system 100. The cloud network optimization module 101can, for example, instantiate new virtual BBUs, terminate existingvirtual BBUs, establish and/or adjust the mapping of the virtual BBUsand the RRHs between one-to-one (e.g., one RRH is assigned to onevirtual BBU) and/or one-to-many (e.g., more than one RRHs are assignedto one virtual BBU). For example, when the network densification isincreased due to capacity, one-to-one BBU-RRH associations can bedefined and sufficient resources (e.g., BBU processing power and/orcapabilities) can be allocated to each virtual BBU. When the wirelessnetwork provide system 100 augments the coverage area of the wirelessnetwork 102 (e.g., as defined by the RRHs 151-155), and/or when lessprocessing power is needed, one-to-many BBU-RRH associations can bedefined so that other RRHs not previously in use can also be associatedwith a given virtual BBU to obtain a wider coverage. Moreover, if lessBBU processing power is being used, hardware (e.g., servers) runningvirtual BBUs can be shut down or put into a hibernation state to reducethe amount of power used by the BBUs. Similarly stated, operation of thevirtual BBUs 111-113 servicing the RRHs 151-155 can be consolidated ontofew virtual BBUs 111-113 and/or onto fewer servers executing the virtualBBUs 111-113. Such optimization allows the system to operate moreefficiently without wasting resources while ensuring that sufficientresources are provided during peak use.

In some instances, when the cloud network optimization module 101changes the topology of the wireless network provider system 100 (e.g.,the BBU-RRH associations), the parameters and/or configuration (e.g.,transmit power, cell identifier, number of licenses, and/or the like) ofthe BBUs can also be updated. Specifically, for example, when the cloudnetwork optimization module 101 of the wireless network provider system100 updates the BBU-RRH mappings (e.g., based on increased networkdensification), parameters and/or a configuration associated with theBBUs and/or RRHs can be identified. For example, the transmit power, thecell identifier, the number of licenses associated with a BBU, and/orother parameters can be updated to optimize and/or improve the networkperformance for the newly defined topology. Moreover, in some instances,when the cloud network optimization module 101 changes the parametersand/or configuration of the BBUs (e.g., transmit power, cell identifier,number of licenses, and/or the like), the topology of the wirelessnetwork provider system 100 can be evaluated and/or changed to providebetter performance. Similarly stated, in such instances, the BBU-RRHmappings can be defined based on and/or as a result of otherconfiguration changes to the BBUs.

For a specific example, the wireless network traffic load anddistribution can be different on different days for a wireless networknear a stadium. On a game day in the stadium, the traffic load increasesdrastically and it is desired to provide the wireless network with moremobile broadband near the stadium. The wireless network provider system100 can be configured to define one-to-one BBU-RRH associations andallocate sufficient resources and processing power to each virtual BBU.On a non-game day in the stadium, the wireless network traffic loaddecreases and less processing power is used to process the wirelessnetwork traffic. Additionally, it may be desirable to provide thewireless network with sufficient coverage for the residents in the samearea of the stadium. The wireless network provider system 100 can beconfigured to terminate some virtual BBUs with low processing and defineone-to-many BBU-RRH associations. In such an instance, a single virtualBBU can handle and/or process the wireless network traffic associatedwith multiple RRHs. In some instances, the one-to-many BBU-RRHassociation can also provide a wider network coverage and/or can useless hardware processing power such that hardware can be shut down orput into a hibernation state. In such an instance, the wireless networkprovider system 100 can be configured to associate other RRHs notpreviously in use with the virtual BBU to define one-to-many BBU-RRHassociations for the purpose of wider network coverage.

In one instance, the cloud network optimization module 101 can changethe Radio Access Technology (RAT) used by the virtual BBUs and thereforechange radio signals transmitted or received by RRHs based on networkuse. For example, the RAT employed by the virtual BBUs supports userdevices with third generation (3G) wireless telephone technology in aspecific area. If the cloud network optimization module 101 detects thatuser devices with second generation (2G) wireless telephone technologynow have higher penetration in that specific area, the cloud networkoptimization module 101 can change the RAT used by the virtual BBU to2G, such that the radio signals transmitted or received by RRHs bettersupport 2G user devices. Similarly stated, based on demand, the RAT usedby specific BBUs can be changes and/or updated to better support thecurrent demand. Using a lower generation RAT can increase the number ofdevices capable accessing the network since higher generation RATs oftensupport lower generation RATs (e.g., 3G devices generally also support2G).

In one instance, for example, four RRHs can service an area. As long asthe total number of subscribers and/or units serviced by the four RRHsis less than a threshold (e.g., less than 50), a single BBU can be usedto service all four RRHs. If, however, the cloud network optimizationmodule 101 receives an indication that the total number of subscribersis greater than or equal to 50, additional BBUs can be assigned to theRRHs. For example, if the indication indicates that a first RRH isservicing 40 subscribers, a second RRH is servicing 10 subscribers, athird RRH is servicing 3 subscribers and a fourth RRH is servicing 15subscribers, the cloud network optimization module 101 can initiate asecond BBU to service only the first RRH. In other words, the first RRHis now only serviced by the second BBU. The second RRH, the third RRHand the fourth RRH can continue to be serviced by a single BBU, becausethe number of subscribers being serviced is not greater than thethreshold (i.e., 50). If the traffic being serviced by the first RRHlater decreases (e.g., to 10 subscribers), the second BBU can beterminated and the first BBU can service the four RRHs. In otherembodiments, any other suitable KPI (e.g., bandwidth) and/or thresholdcan be used. In still other embodiments, a combination of KPIs and/orthresholds can be used to determine when to rebalance, instantiateand/or terminate BBUs.

In some instances, the physical RRHs 151-155 and the BBU Pool Server 105are not permanently commissioned for supporting peak wireless networktraffic; instead, only a permanent set of cost effective RRHs 151-155are deployed and connected to virtual base stations by assigning on anon-demand basis virtual BBUs from the BBU Pool Server 105. In someembodiments, the virtual BBUs can be connected to a set of RRHs via atransmission network (e.g., front haul 165 in FIG. 1B).

In some implementations, for example, in an LTE network, the cloudnetwork optimization module 101 can be configured to simplify theimplementation of the high-bandwidth low-latency X2 interfacesconnecting the geographically distributed virtual eNodeBs. The X2interfaces can be configured to run within the same computing frame,chassis, rack and/or device that hosts the multiple virtualized BBUs.

In some implementations, the cloud network optimization module 101 canbe configured to allow operators to consider a centralized approachwithin the wireless network 102 to better combine the wireless networktraffic load management and the wireless network interferencemanagement. The cloud network optimization module 101 can, for example,implement advanced LTE features such as Cooperative Multi-Point (CoMP)and enhanced intercell interference coordination (eICIC) by jointlyprocessing and scheduling signals between virtual BBUs. The cloudnetwork optimization module 101 can be, for example, implemented inheterogeneous networks (HetNets) involving multiple network technologies(UMTS, Wi-Fi, LTE, etc.) and overlapping macro and micro cells thatshare the same carrier.

As shown in FIG. 1B, the cloud-radio access network (“C-RAN”) 100Bincludes virtual BBUs (v-BBUs) 110B within a BBU pool 105B, and a set ofRRHs 150B connected through a front haul 165B. The front haul 165B canbe a network, connection and/or set of connections between the v-BBUs110B and the set of RRHs 150B. The v-BBUs 110B, the BBU pool 105B, andthe set of RRHs 150B are structurally and/or functionally similarly tothe virtual BBUs (e.g., 111, 112, and 113), the BBU Pool Server 105, andthe set of RRHs (e.g., 151-155) shown and described with respect to FIG.1A, respectively. In some implementations, the virtual BBUs 110B can beconnected to a set of RRHs 150B via a transmission network (e.g., fronthaul 165B in FIG. 1B). The cloud network optimization module 101 (notshown in FIG. 1B), as described in FIG. 1A, can be physically located oroperatively deployed within the front haul 165B to perform thevirtualization and optimization process. In such an implementation, thecloud network optimization module can also act as a multiplexer and/orswitch to ensure that signals received from the RRHs 150B are sent tothe appropriate and/or associated v-BBUs 110B. Similarly, the cloudnetwork optimization module can ensure that the signals received fromthe v-BBUs 110B are sent to the appropriate and/or associated RRHs 150B.In some implementations, the cloud network optimization module 101, asdescribed in FIG. 1A, can be configured to be separate from the fronthaul to perform the virtualization and optimization process.

Note that the components and/or devices of the wireless network providersystem 100 described with respect to FIG. 1A and the C-RAN 100Bdescribed with respect to FIG. 1B can be centralized or distributed. Forexample, the cloud network optimization module 101 of FIG. 1A can be ina location remote from the BBU pool server 105 and/or the virtual BBUhousing device 110. In such instances, the cloud network optimizationmodule 101 can be operatively coupled to the BBU pool server 105 and/orthe BBU housing device 110 via a network (not shown in FIG. 1A).Similarly, while shown as being within a single virtual BBU housingdevice 110, the virtual BBUs 111-113 shown in FIG. 1A can be located indifferent locations and/or instantiated by different devices. Forexample, a first virtual BBU can be instantiated by a device (e.g., afirst server) in a first geographic location and a second virtual BBUcan be instantiated by a device (e.g., a second server) in a secondgeographic location.

FIG. 2 is a system block diagram of a cloud network optimization module201, according to an embodiment. The cloud network optimization module201 can be structurally and functionally similar to the cloud networkoptimization module 101 shown and described with respect to FIG. 1. Thecloud network optimization module 201 can be coupled to a wirelessnetwork (not shown in FIG. 2) that is similar to the wireless network102 shown and described with respect to FIG. 1. As shown in FIG. 2, thecloud network optimization module 201 can include a processor 280, amemory 270, a monitor module 210, a detector module 220, an optimizationmodule 230, a virtual resource configuration module 240, and acommunications interface 290. In some implementations, the cloud networkoptimization module 201 can be within a single physical device. In someimplementations, the cloud network optimization module 101 can behardware or software executing in hardware. For example, the cloudnetwork optimization module 101 can be software executing on the BBUpool server 105. In some implementations, the cloud network optimizationmodule 201 can be included within multiple physical devices (e.g.,operatively coupled by a network), each of which can include one ormultiple modules and/or components shown in FIG. 2.

Each module or component in the cloud network optimization module 201can be operatively coupled to each remaining module or component. Eachmodule or component in the cloud network optimization module 201 can beany combination of hardware and/or software (stored and/or executing inhardware) capable of performing one or more specific functionsassociated with that module. In some implementations, a module or acomponent in the cloud network optimization module 201 can include, forexample, a field-programmable gate array (FPGA), an application specificintegrated circuit (ASIC), a digital signal processor (DSP), and/or thelike.

The memory 270 can be, for example, a random-access memory (RAM) (e.g.,a dynamic RAM, a static RAM), a flash memory, a removable memory, and/orso forth. In some embodiments, the memory 270 can include, for example,a database, process, application, virtual machine, and/or some othersoftware modules (stored and/or executing in hardware) or hardwaremodules configured to execute a virtualization and optimization processand/or one or more associated methods for optimizing or improving theperformance of the wireless network (e.g., via the communicationsinterface 290). In such implementations, instructions of executing thevirtualization and optimization process and/or the associated methods(e.g., such as instructions for the monitor module 210, detector module220, optimization module 230 and/or the virtual resource configurationmodule 240) can be stored within the memory 270 and executed at theprocessor 280.

The communications interface 290 can include and/or be configured tomanage one or multiple ports of the cloud network optimization module201. In some instances, for example, the communications interface 290can include one or more line cards, each of which can include one ormore ports (operatively) coupled to devices (e.g., BBU pool server 105,base stations, etc.) in the wireless network. A port included in thecommunications interface 290 can be any entity that can activelycommunicate with a coupled device or over a network. In someembodiments, such a port need not necessarily be a hardware port, butcan be a virtual port or a port defined by software. In someembodiments, the connections between the communications interface 290and the devices in the wireless network provider system can implement aphysical layer using, for example, fiber-optic signaling, electricalcables, wireless connections, or other suitable connection means. Insome embodiments, the communications interface 290 can be configured to,among other functions, receive data and/or information collected orreceived from the wireless network provider system, and sendconfiguration modifications, commands, and/or instructions to thedevices in the wireless network provider system.

The processor 280 can be configured to control, for example, theoperations of the communications interface 290, write data into and readdata from the memory 270, and execute the instructions stored within thememory 270. The processor 280 can also be configured to control, forexample, the operations of the monitor module 210, the detector module220, the optimization module 230, and the virtual resource configurationmodule 240, as described in further detail herein. In some embodiments,the monitor module 210, the detector module 220, the optimization module230, and the virtual resource configuration module 240 are stored in thememory 270 and executed by the processor 280. In some embodiments, underthe control of the processor 280 and based on the methods or processesstored within the memory 270, the monitor module 210, the detectormodule 220, the optimization module 230, and the virtual resourceconfiguration module 240 can be configured to collectively execute avirtualization and optimization process to optimize or improve theperformance of the wireless network, as described in further detailherein.

The monitor module 210 can monitor the performance of the wirelessnetwork. Specifically, the monitor module 210 can be configured tocollect or receive data and/or information from the RRHs 151-155 of thewireless network provider system 100 and/or from the wireless network102 (as shown in FIG. 1A). In some instances, the monitor module 210 canbe configured to collect or receive observation data from one ormultiple wireless communication devices (e.g., cellular phones) thatcommunicate with a virtual BBU. In such instances, the observation datacan be measured, received and/or collected based on, for example, thesignals that are received from the virtual BBU at the wirelesscommunication devices, or the signals that are sent from the wirelesscommunication devices to the virtual BBU. In some other instances, themonitor module 210 can also be configured to collect or receiveobservation data from the virtual BBUs. Additionally, in some instances,data can be collected or received from the BBUs and/or wirelesscommunication devices in the wireless network periodically inobservation windows. Such an observation window can be, for example, onehour.

In some instances, data collected or received at the monitor module 210can include a set of indicators that can be used to determine theperformance of the wireless network. The set of indicators can include,for example, an admission indicator, a congestion indicator, aperformance indicator, a mobile level measurement, a networkconfiguration parameter, an indication of a network alarm, an availableprocessing power associated with the virtual BBUs, a load associatedwith each virtual BBU in operation, and/or the like. In someembodiments, the indicators can include site-related configurationparameters, network-related configuration parameters, sector-relatedconfiguration parameters, RF-carrier-related configuration parameters,power indicators, throughput indicators, and/or various KPIs.

The site-related configuration parameters (configuration parameters persite) can include, for example, name of the site, longitude, latitudeand altitude of the site, etc. The sector-related configurationparameters (configuration parameters per sector) can include, forexample, site name, sector name, active/inactive status, frequency band,number of carriers for the sector, service for each carrier, heightabove the site ground level, antenna gain (e.g., in dBi), mechanicaldowntilt, electrical downtilt, total sector power (e.g., in dBm), etc.The RF-carrier-related configuration parameters (configurationparameters per RF carrier) can include, for example, site name, sectorname, carrier number, carrier RF frequency, PN (pilot number) offset,active set threshold (e.g., in dB), maximum available power for thecarrier (e.g., in dBm), pilot power (e.g., in dBm), synchro power (e.g.,in dBm), paging power (e.g., in dBm), etc.

The KPIs can include, for example, carrier, site, sector, cell, and/ormobile level KPIs. The cell level KPIs can include, for example, atransmitted radio power level value of a cell, a successful call rate(“SCR”) value of a cell, traffic statistical values associated with acell, handover statistical values associated with a cell, a drop callrate (“DCR”) value associated with a cell, an admission indicator, acongestion indicator, and/or the like. Specifically, the carrier levelKPIs can include, for example, year/month/day/time, site name, sectorname, carrier number, total average transmitted power (e.g., in dBm),uplink total noise (e.g., in dBm), downlink/uplink load factor (e.g., inpercentage), uplink interference noise rise (e.g., in dB), number ofdownlink/uplink radio links used, connection success rate (e.g., inpercentage), average number of attempted users, average number ofconnected users, average number of used codes, ratio of handoff (e.g.,in percentage), connection success, downlink/uplink throughput (e.g., inkbps), etc.

The detector module 220 can detect degraded operational conditions for aset of BBUs in the wireless network. Specifically, the detector module220 can receive the observation data (e.g., indicators) collected orreceived at the monitor module 210. Based on the collected or receivedobservation data, the detector module 220 can detect the BBUs thatdemonstrate degraded performance in certain performance criteria. Insome instances, the detector module 220 can determine if the receivedobservation data meet certain performance criteria, cross a definedperformance threshold, and/or the like.

In some embodiments, one or more performance metrics can be used tocharacterize the current mapping performance of the BBU-RRH pairs in thewireless network. Such performance metrics can include, for example, SCR(e.g., averaged over an observation window within a critical zone or acell), dropped call rate (DCR), capacity (e.g., throughput of, forexample, a critical zone or a cell), capacity increase ratio (e.g.,change in the throughput of, for example, a critical zone or a cellrelative to the initial traffic associated with that critical zone orcell), the power supplied to a base station, and/or the like.

In some embodiments, the detector module 220 can monitor the performanceof the wireless network in terms of the frequency of negative ordegraded performance incidents. For example, the detector module 220 canbe configured to, based on the received data from the monitor module210, detect BBU-RRH pairs that have repeated incidents of degradedperformance (e.g., low SCR). In some embodiments, the detector module220 can also receive indicators of the available processing power of thevirtual BBUs. In such embodiments, the detector module 220 can alsodetect and/or identify virtual BBUs and/or processing resources (e.g.,servers executing the virtual BBUs) that are under-utilized and/orover-utilized.

The optimization module 230 can determine how to reconfigure thetopology and configuration of the wireless network provider system.Specifically, the optimization module 230 can determine when toinstantiate new virtual BBU(s), terminate existing virtual BBU(s),establish and/or adjust the mapping of the virtual BBUs and the RRHs(e.g., between one-to-one (e.g., one RRH is assigned to a virtual BBU)and/or one-to-many (e.g., more than one RRHs are assigned to a virtualBBU)). Specifically, the optimization module 230 can receive thedegraded RRH data (e.g., data from the RRHs that demonstrate degradedperformance in certain performance criteria) collected at the detectormodule 220. Based on the received degraded RRH data, the optimizationmodule 230 can determine how to map the network to establish an improvedrelationship between the virtual BBU(s) and the RRH(s).

The virtual resource configuration module 240 can be configured toexecute instructions to instantiate new virtual BBU(s), terminateexisting virtual BBU(s), establish and/or adjust the mapping of thevirtual BBUs and the RRHs (e.g., between one-to-one (e.g., one RRH isassigned to a virtual BBU) and one-to-many (e.g., more than one RRHs areassigned to a virtual BBU)), based on the optimization data receivedfrom the optimization module 230.

For example, the monitor module 210 can collect data (e.g., KPIs) fromthe RRHs (e.g., 151-155 in FIG. 1A) and/or the BBUs (e.g., 111-113 inFIG. 1A) to monitor the performance of the wireless network. When adensification of the wireless network in an area increases (e.g., a gameday in a stadium), the detector module 220 can detect a specific BBU-RRHassociation(s) that demonstrates low performance in certain performancecriteria based on the observation data collected at the monitor module210. The optimization module 230 can receive the degraded data and candetermine that the low performing BBU is associated with four RRHs.Similarly stated, the low performing BBU is in a 1-4 BBU-RRHassociation. The optimization module 230 can instruct the virtualresource configuration module 240 to instantiate a new virtual BBU andestablish a 1-1 BBU-RRH association to improve the performance of thelower performing BBU-RRH association. The virtual resource configurationmodule 240 receives and executes the instructions from the optimizationmodule 230 to instantiate a new virtual BBU to service one or more RRHfrom the lower performing BBU. The communications interface 290 sendsthe virtualization instruction to the BBU pool server (e.g., 105 in FIG.1A) to instantiate the new virtual BBU and establish a 1-1 BBU-RRHassociation to improve the performance of the wireless network. Themonitor module 210 can continue to monitor the performance of thewireless network and repeat the process as needed or desired.

FIGS. 3A-3B are block diagrams that illustrate two front haul deploymentoptions, according to two embodiments. The front haul (e.g., 165 asshown in FIG. 1B) can include a transport network that carries signalingand traffic data between RRHs and the virtual BBUs. The front haulstandards can include, for example, common public radio interface (CPRI)and open base station architecture initiative (OBSAI). The physicalmedium of the front haul can be fiber, microwave, and/or any other highbandwidth technology.

FIG. 3A shows a full centralization front haul, according to anembodiment. In some embodiments, the virtual BBU 310 can support Layer1, Layer 2 and Layer 3 traffic and signaling as well as operations andmaintenance (O&M) functionality. The RRHs 350 can be radio accesstechnology (RAT) agnostic allowing operators to dynamically switch theradio access technology when needed (e.g., LTE, UMTS, GSM, etc.). Inother words, if Layer 1 is centralized, the communication informs theRRH what Layer 1 technology to use. This increases flexibility sincemultiple technologies at an RRH (assuming capabilities) can be used, butalso increases bandwidth use. The full centralization front haul 361 canhave multi-RAT support, resource sharing, and sufficient architecturefor coordinated multi-point (CoMP) transmission and reception. As such,the full centralization front haul 361 can use high bandwidth fortransporting the digitized L1 signals between a virtual BBU and the RRH.

FIG. 3B shows a partial centralization front haul, according to anembodiment. In some embodiments, the virtual BBUs 310B can be configuredto support Layer 2, Layer 3 and O&M support, with Layer 1 residing atthe RRH 350B level. The partial centralization front haul 365 may lackthe flexibility as the full centralization front haul 361, but uses lessbandwidth. In other words, if Layer 1 communication is not centralizedor is partially centralized, the BBUs can provide less information tothe RRHs, thus reducing the bandwidth. In one example, 2 percent to 5percent of the bandwidth used by the full centralization front haul 361,as shown in FIG. 3A, may be used by the partial centralization fronthaul 365, as shown in FIG. 3B. As the full centralization front haul 361supports Layer 1 traffic and signaling, it allows RRHs 350 to betechnology agnostic and not limited to a specific technology (e.g., LTE,GSM, etc.). The partial centralization front haul 365, however, does notsupport Layer 1 traffic and signaling, and therefore the RRHs convertthe information received from the BBUs into the right Layer 1 signalspecific to a technology. Thus, the partial centralization front haul365 is more dedicated to specific technology (e.g., LTE, GSM, etc.).

FIG. 4 is a schematic diagram that illustrates a wireless network,according to an embodiment. As shown in FIG. 4, wireless networks mayhave a combination of physical stand-alone network elements 475 (e.g.,legacy deployed macro cells) and cloud-based radio access networkislands 480. Distributed self-optimizing network elements (“D-SON”) 475can be configured to run at stand-alone; virtual network elements,whether hybrid and/or centralized self-optimizing, can be configured torun at the network level. As such, each cloud-based radio access networkisland 480 can have its own self-optimizing network functions and/orcapabilities connected to the centralized SON module 471 serving themacro-cells. Similarly stated, the centralized/hybrid SON module 471 cancommunicate, control and/or coordinate with the SON functions associatedwith the cloud-based radio access network island 480 (e.g., caninstantiate, rebalance and/or terminate BBUs) and with the D-SON 475functions running at the network elements. In some embodiments, thecentralized SON module 471 can also include the virtual BBUs used tocontrol the cloud-based radio access network islands 480. In otherembodiments, the virtual BBUs are not included at the centralized SONmodule 471, but on a separate device operatively coupled to thecentralized SON module 471. In some embodiments, the D-SON 475 canoperate independent of the centralized SON module 471. In otherembodiments, the distributed SON systems 475 can coordinate with thecentralized SON module 471 to improve operation of the entire network.In such embodiments, a single centralized SON module 471 can controland/or provide signals to the legacy D-SON network (e.g., having BBUscollocated with the RRHs) as well as the cloud-based SON portion of thenetwork (e.g., the cloud-based radio access network island 480). Thisallows networks to implement such cloud-based SONs in a portion of anetwork without replacing the entire network at a given time.

FIG. 5 is a flow chart illustrating a method 500 for dynamicvirtualization and optimization in a wireless network, according to anembodiment. The optimization method 500 can be executed at, for example,a cloud network optimization module such as the cloud networkoptimization module 201 shown and described with respect to FIG. 2. Thecloud network optimization module can include, for example, a monitormodule, a detector module, an optimization module, and a virtualresource configuration module, which are similar to the modules of thecloud network optimization module 201 shown and described with respectto FIG. 2. Furthermore, the cloud network optimization module can beoperatively coupled to a wireless network that is similar to thewireless network 102 shown and described with respect to FIG. 1A.

At 502, the cloud network optimization module monitors a set ofperformance indicators associated with a first network topology of a setof virtual baseband units (BBUs) servicing a set of remote radio heads(RRHs) of a wireless network provider system. The set of performanceindicators can include, for example, an admission indicator, acongestion indicator, a power indicator, a mobile level measurement, anetwork configuration parameter, an indication of a network alarm, linkconnection information, a throughput indication, a key performanceindicator (KPI), an available processing power associated with thevirtual BBUs, a load associated with each virtual BBU in operation,and/or the like.

At 504, the cloud network optimization module detects an operationalcondition of the wireless network provider system based on at least onevalue associated with the set of performance indicators at a first time.For example, the operational condition can be a condition when one valueassociated with the set of performance indicators fails to meet aperformance criteria.

At 506, the cloud network optimization module defines, based on theoperational condition, a second network topology for the set of virtualbaseband units. In the second network topology, there can be morevirtual baseband units than the virtual baseband units in the firstnetwork topology servicing the same set of remote radio heads. Inanother implementation, there can be less virtual baseband units thanthe virtual baseband units in the first network topology servicing thesame set of remote radio heads, thus reducing power used by the virtualbaseband units. The associations between each virtual baseband unit andeach remote radio heads can be different in the second network topologyfrom the first network topology. For example, the associations of thevirtual BBUs and the RRHs can be one-to-one (e.g., one RRH is assignedto a virtual BBU) or one-to-many (e.g., more than one RRHs are assignedto a virtual BBU).

At 508, the cloud network optimization module sends a signal to avirtual baseband unit pool manager to reconfigure the wireless networkprovider system in the second network topology at a second time afterthe first time. For example, the virtual baseband unit pool manager caninstantiate a virtual baseband unit such that the virtual baseband unitis added to the set of virtual baseband units, terminates a virtualbaseband unit from the set of virtual baseband units, or adjusts anassociation or mapping of the set of virtual baseband units to the setof remote radio heads.

It is intended that the systems and methods described herein can beperformed by software (stored in memory and/or executed on hardware),hardware, or a combination thereof. Hardware modules may include, forexample, a general-purpose processor, a field programmable gate array(FPGA), and/or an application specific integrated circuit (ASIC).Software modules (executed on hardware) can be expressed in a variety ofsoftware languages (e.g., computer code), including Unix utilities, C,C++, Java™, Ruby, SQL, SAS®, the R programming language/softwareenvironment, Visual Basic™, and other object-oriented, procedural, orother programming language and development tools. Examples of computercode include, but are not limited to, micro-code or micro-instructions,machine instructions, such as produced by a compiler, code used toproduce a web service, and files containing higher-level instructionsthat are executed by a computer using an interpreter. Additionalexamples of computer code include, but are not limited to, controlsignals, encrypted code, and compressed code. Each of the devicesdescribed herein, for example, devices S1, S2, and S3, nodes, serversand/or switches, etc. can include one or more processors as describedabove.

Some embodiments described herein relate to devices with anon-transitory computer-readable medium (also can be referred to as anon-transitory processor-readable medium or memory) having instructionsor computer code thereon for performing various computer-implementedoperations. The computer-readable medium (or processor-readable medium)is non-transitory in the sense that it does not include transitorypropagating signals per se (e.g., a propagating electromagnetic wavecarrying information on a transmission medium such as space or a cable).The media and computer code (also can be referred to as code) may bethose designed and constructed for the specific purpose or purposes.Examples of non-transitory computer-readable media include, but are notlimited to: magnetic storage media such as hard disks, floppy disks, andmagnetic tape; optical storage media such as Compact Disc/Digital VideoDiscs (CD/DVDs), Compact Disc-Read Only Memories (CD-ROMs), andholographic devices; magneto-optical storage media such as opticaldisks; carrier wave signal processing modules; and hardware devices thatare specially configured to store and execute program code, such asApplication-Specific Integrated Circuits (ASICs), Programmable LogicDevices (PLDs), Read-Only Memory (ROM) and Random-Access Memory (RAM)devices. Other embodiments described herein relate to a computer programproduct, which can include, for example, the instructions and/orcomputer code discussed herein.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Where methods and steps described above indicate certainevents occurring in certain order, the ordering of certain steps may bemodified. Additionally, certain of the steps may be performedconcurrently in a parallel process when possible, as well as performedsequentially as described above. Although various embodiments have beendescribed as having particular features and/or combinations ofcomponents, other embodiments are possible having any combination orsub-combination of any features and/or components from any of theembodiments described herein. Furthermore, although various embodimentsare described as having a particular entity associated with a particularcompute device, in other embodiments different entities can beassociated with other and/or different compute devices.

1-21. (canceled)
 22. A non-transitory computer-readable medium storinginstructions, the instructions comprising: one or more instructionsthat, when executed by one or more processors of a user device, causethe one or more processors to: monitor a plurality of performanceindicators associated with a first network topology of a set of virtualbaseband units servicing a plurality of remote radio heads of thewireless network provider system; detect an operational condition of awireless network provider system based on at least one value associatedwith the plurality of performance indicators at a first time; define,based on the operational condition, a second network topology for theset of virtual baseband units; and send a signal to a virtual basebandunit pool manager to reconfigure the wireless network provider system inthe second network topology at a second time after the first time. 23.The non-transitory computer-readable medium of claim 22, wherein the oneor more instructions further cause the one or more processors to atleast one of: instantiate a virtual baseband unit such that the virtualbaseband unit is added to the set of virtual baseband units, terminate avirtual baseband unit from the set of virtual baseband units, or adjusta mapping of the set of virtual baseband units to the plurality ofremote radio heads.
 24. The non-transitory computer-readable medium ofclaim 22, wherein each remote radio head from the plurality of remoteradio heads is associated with a virtual baseband unit from the set ofvirtual baseband units in the second network topology.
 25. Thenon-transitory computer-readable medium of claim 22, wherein multipleremote radio heads from the plurality of remote radio heads are assignedto a single virtual baseband unit from the set of virtual baseband unitsin the second network topology.
 26. The non-transitory computer-readablemedium of claim 22, wherein the plurality of performance indicatorsinclude at least one of an admission indicator, a congestion indicator,a power indicator, a mobile level measurement, a network configurationparameter, an indication of a network alarm, link connectioninformation, a throughput indication, or a key performance indicator(KPI).
 27. The non-transitory computer-readable medium of claim 22,wherein the plurality of performance indicators include at least one ofan admission indicator, a congestion indicator, a successful call rate(SCR), a dropped call rate (DCR), a capacity of a cell, or a capacityincrease ratio of the cell, the plurality of performance indicatorsbeing averaged over an observation window.
 28. The non-transitorycomputer-readable medium of claim 22, wherein each remote radio headfrom the plurality of remote radio heads is agnostic to a radio accesstechnology (RAT).
 29. The non-transitory computer-readable medium ofclaim 22, wherein each remote radio head from the plurality of remoteradio heads is specific to a radio access technology (RAT).
 30. Adevice, comprising: a memory; and a processor, operatively coupled tothe memory, to: monitor a plurality of performance indicators associatedwith a wireless network provider system, the wireless network providersystem including a first set of virtual baseband units servicing at afirst time a set of remote radio heads from a plurality of remote radioheads to define a first network topology, define an operationalcondition of the wireless network provider system, at the first time,when at least one value associated with the plurality of performanceindicators fails to meet a performance criterion; and send a signal to avirtual baseband unit pool manager, at a second time after the firsttime, such that the virtual baseband unit pool manager causes a secondset of virtual baseband units to service the set of remote radio headsfrom the plurality of remote radio heads after the second time to definea second network topology different from the first network topology. 31.The device of claim 30, wherein the first set of virtual baseband unitsincludes a greater number of virtual baseband units than the second setof virtual baseband units.
 32. The device of claim 30, wherein the firstset of virtual baseband units includes a fewer number of virtualbaseband units than the second set of virtual baseband units.
 33. Thedevice of claim 30, wherein the processor is further to: send anothersignal to the virtual baseband unit pool manager, at a third time afterthe first time, such that the first set of virtual baseband units andthe second set of virtual baseband units collectively service the set ofremote radio heads after the third time, the second set of virtualbaseband units being mutually exclusive from the first set of virtualbaseband units.
 34. The device of claim 30, wherein the processor isfurther to: send another signal to the virtual baseband unit poolmanager, at a third time after the first time, to terminate the firstset of virtual baseband units such that the first set of virtualbaseband units stops servicing the set of remote radio heads.
 35. Thedevice of claim 30, wherein the plurality of performance indicatorsinclude at least one of an admission indicator, a congestion indicator,a transmitted radio power level of a cell, a successful call rate valueof a cell, a traffic statistical value of a cell, a drop call rate valueof a cell, an averaged transmitter radio power level, an uplink totalnoise value, or a downlink/uplink load factor.
 36. A method, comprising:monitoring a plurality of performance indicators associated with a firstnetwork topology and configuration of a wireless network providersystem, the first network topology and configuration including a firstset of virtual baseband units servicing a first plurality of remoteradio heads of the wireless network provider system; defining, at afirst time and based on at least one value associated with the pluralityof performance indicators, a second network topology and configurationof the wireless network provider system, the second network topology andconfiguration including a second set of virtual baseband units servicinga second plurality of remote radio heads of the wireless networkprovider system; and sending a signal to a virtual baseband unit poolmanager to transition the wireless network provider system from thefirst network topology and configuration to the second network topologyand configuration at a second time after the first time.
 37. The methodof claim 35, wherein: the first plurality of remote radio heads is thesame as the second plurality of remote radio heads, the second set ofvirtual baseband units includes the first set of virtual baseband unitsand a third set of virtual baseband units, and the sending includessending the signal to instruct the virtual baseband unit pool manager toinstantiate the third set of virtual baseband units.
 38. The method ofclaim 35, wherein: the first plurality of remote radio heads is the sameas the second plurality of remote radio heads, the first set of virtualbaseband units includes the second set of virtual baseband units and athird set of virtual baseband units, and the sending includes sendingthe signal to instruct the virtual baseband unit pool manager toterminate the third set of virtual baseband units.
 39. The method ofclaim 35, wherein: a virtual baseband unit from the first set of virtualbaseband units services a first remote radio head but not a secondremote radio head in the first network topology and configuration, andthe virtual baseband unit from the first set of virtual baseband unitsservices the first remote radio head and the second remote radio head inthe second network topology and configuration.
 40. The method of claim35, wherein: a virtual baseband unit from the first set of virtualbaseband units services a first remote radio head and a second remoteradio head in the first network topology and configuration, and thevirtual baseband unit from the first set of virtual baseband unitsservices the first remote radio head but not the second remote radiohead in the second network topology and configuration.
 41. The method ofclaim 35, wherein the first plurality of remote radio heads is agnosticto a radio access technology (RAT).
 42. The method of claim 35, wherein:a virtual baseband unit from the first set of virtual baseband unitsservices a multiple remote radio heads in the first network topology andconfiguration, and the virtual baseband unit from the first set ofvirtual baseband units services only one remote radio head in the secondnetwork topology and configuration.